NOTE: Alpha versions have not yet completed the full suite of tests by the Xamarin QA team. That said, customer reports of any regressions (or bugs that are incorrectly marked "fixed") are still much appreciated, even if the problem would have eventually been caught during the full QA testing process.

Previous versions, downgrading

You can downgrade back to the current Stable version by switching updater channels.

You can downgrade back to the previous Stable versions (from before April 29) by manually reinstalling each old package (see also the article about downgrading). The links to the previous Stable versions are:

Guidelines for this thread

Hopefully this thread will help answer "what regressions have been fixed compared to the current Stable version?" and "what might break if I update to this release?"

If you find a new problem that is specific to this version, please file a bug report (if this link redirects to the top-level https://kb.xamarin.com/ page the first time you click it, try clicking it once more).

Please discuss older bugs that are unchanged in this release compared to the previous Stable version in Bugzilla instead.

Of course for questions and discussions about topics other than bugs, feel free start new forum threads.

Bug 29220 - [XamarinVS] [iOS] [Android] "ERROR: Value cannot be null. Parameter name: project" when opening and building projects. So far, this problem appears to be related to specifics of the system configuration. If anyone happens to notice one particular difference between a working project and a failing project (or a computer without the problem and a computer with the problem), be sure to let us know right away. Partial workaround: uninstall the Test Cloud integration: https://bugzilla.xamarin.com/show_bug.cgi?id=29680#c2.

Bug 29568 - [Android] "No resource found that matches the given name", for AppCompat resources in the Android Support library.

Non-public bug 29866 - [Android] Windows only: "System.InvalidOperationException: Can't not find the nested type" when building with the linker enabled.

Non-public Bug 29172 - [Android] "'...Resource' does not contain a definition for `Id'" (for example, when using the Scandit component).

Remaining known issues from the April 29 Stable Channel release, with more common or severe issues near the top

(This list should get smaller as new Alpha builds are published over the coming week.)

Bug 29326 - [Android] String resources defined in NuGet packages overwrite string resources defined in app project, causing the displayed app name to be incorrect for example. Workaround: avoid using the same string key that is used in the NuGet packages.

Well I tried to downgrade and now I am getting a new error:
Error 146 The "LinkAssemblies" task failed unexpectedly.
Xamarin.Android.XamarinAndroidException: error XA2006: Reference to metadata item 'System.Void Android.Widget.AbsListView::SetSelectionFromTop(System.Int32,System.Int32)' (defined in 'Xamarin.Forms.Platform.Android, Version=1.4.0.0, Culture=neutral, PublicKeyToken=null') from 'Xamarin.Forms.Platform.Android, Version=1.4.0.0, Culture=neutral, PublicKeyToken=null' could not be resolved. ---> Mono.Cecil.ResolutionException: Failed to resolve System.Void Android.Widget.AbsListView::SetSelectionFromTop(System.Int32,System.Int32)
at Mono.Linker.Steps.MarkStep.MarkMethod(MethodReference reference)
at Mono.Linker.Steps.MarkStep.MarkInstruction(Instruction instruction)
at Mono.Linker.Steps.MarkStep.MarkMethodBody(MethodBody body)
at Mono.Linker.Steps.MarkStep.ProcessMethod(MethodDefinition method)
at Mono.Linker.Steps.MarkStep.ProcessQueue()
at Mono.Linker.Steps.MarkStep.Process()
at Mono.Linker.Steps.MarkStep.Process(LinkContext context)
at Mono.Linker.Pipeline.Process(LinkContext context)
at MonoDroid.Tuner.Linker.Process(LinkerOptions options, LinkContext& context)
at Xamarin.Android.Tasks.LinkAssemblies.Execute()
--- End of inner exception stack trace ---
at Xamarin.Android.Diagnostic.Error(Int32 code, Exception innerException, String message, Object[] args)
at Xamarin.Android.Tasks.LinkAssemblies.Execute()
at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
at Microsoft.Build.BackEnd.TaskBuilder.d__20.MoveNext()

The Xamarin.Forms.Platform.Android that is being referenced is in my Packages/Xamarin.Forms.1.4.2.6359 directory. Do I need to do anything else to be able to get moving again?

EDIT: I had zipped up a backup and I was able to use that without fail. So I learned a VERY important lesson. When upgrading xamarin, make sure to backup all code before hand. It was invaluable for me.

Related to BradChase's post from earlier in the thread, so far the Xamarin QA team hasn't come across a sample that reproduces this error. If anybody might be able to zip up and attach a test case on a new bug report (or attach it directly on this thread, or send it in via [email protected]), that would be perfect. See the bug filing KB article for some additional hints and tips about filing a bug report and minimizing the test case. (If the link to the KB article redirects to the top-level kb.xamarin.com/ page the first time you click it, try clicking it once more.) Thanks!

OK, downloaded and installed the latest Alpha (3.11.546) to get the fix for the Bug 29568. The fix works fine, however, I'm now getting the following issue when doing a Release build with Linking set to SDK assemblies only

@EstebanGimbernat, hmm. That sounds like the same underlying problem as Bug 29731. To be safe, we should probably get a bug filed for the specific case of Android.Speech.Tts.TextToSpeech.

I haven't yet found the right combination of versions where that type is marked as deprecated. (I see several methods, properties, and fields within that type that are marked as deprecated, but those all match the deprecations listed in the Android documentation.)

So 2 quick follow-up questions:

Is it the Android.Speech.Tts.TextToSpeech class itself that is coming up as deprecated, or is it some method, property, or field within that class?

@BrendanZagaeski the latest alpha 3.11.558 failed to install for me on Windows. It left the Visual Studio extension broken. I had to uninstall and reinstall stable to get it working again. I haven't tried to reinstall the alpha again since. Let me know if you need more debugging info. Not sure if it is just me.

@BrendanZagaeski all right, that's what I found:
1- Method Speak is marked depracated and according to documentation is above api 21 that originally Speak Mehod is obsolete, and actually, It preseverd the name, only the type of paramaters changed.
2- I'm targeting api 19

@EstebanGimbernat, I can confirm that TextToSpeech.Speak(string, QueueMode, IDictionary<string, string>) is correctly marked deprecated on API 21 in Xamarin.Android. (And the other overrides of Speak() are not marked as deprecated.)

Unfortunately, when targeting Xamarin.Android to API 19, I'm also seeing that TextToSpeech.Speak(string, QueueMode, IDictionary<string, string>) is correctly not marked as deprecated.

Given that result, if you get a chance the most direct way forward would probably be to submit a test case that shows the problem on a new bug report (if this link redirects to the top-level kb.xamarin.com/ page the first time you click it, try clicking it once more). I think there's a good chance you might be able to create a sufficient test case with the following steps:

Make a copy of your original app project that shows the problem.

Delete all the files from the project except for MainActivity.cs (or whichever file contains the "MainLauncher" activity) and AndroidManifest.xml.

(If you like, a slightly simpler way to provide a test case could be to delete the bin, obj, Components, and packages folders, and attach the whole solution folder for your app to the bug report, optionally marking the bug report "private" to restrict visibility to Xamarin.)

Brendan, When I have time I will upgrade again and send you what I believe you need. I just have to have some spare time to upgrade, limit the solution down to the bare essentials, and make sure I can still get the issue. Sorry I cant be of more help with it right now, but we will need to upgrade at some point here so it has to happen.

When will you look into the "Non-public Bug 28995 - [Android] On certain devices apps crash rarely due to "System.ExecutionEngineException: SIGILL"." - bug?

It seems to affect all Samsung S6 devices. I can't even run the default android-application from a new project in Xamarin Studio without having the SIGILL crash. Our development has stalled since we're using hardware features (need to debug and test on real device) and only have an S6 Edge device..

Thanks for the reports @ErikArenhill, @BenjaminRush. I have marked both of you as affected customers on the bug report to help increase its prioritization. Bug 28995 is currently set as a top priority for the next service release. Alpha channel versions of that new service release will be published after this current Alpha/Beta version is promoted to Stable (tentatively by the end of May).